This application requests core and program development support for a broadly-based program of research related to human development which may assist in finding causes and means of prevention of mental retardation or in finding means of ameliorating the effects of mental retardation. The mental retardation research program at the Children's Hospital Research Foundation (CHRF) is based within the Institute for Developmental Research (IDR) and includes many of the research divisions of the CHRF. Numerous core services and facilities available in the IDR support this research program. Funds are requested for continuation of these services, for the addition of computational and electron microscopic core services and for the recruitment and initial research support of new scientific and administrative personnel, including a new program director.